Articulated conduit support arms are typically used to provide articulated support of various electrically-powered devices such as computer monitors, lamps, and illuminated magnifying lenses. Articulated conduit support arms are designed to be able to be moved and repositioned while supporting the weight of the device. The articulated conduit support arms also provide for the protection and concealment of electric cables and power lines connected to the device being supported.
Articulated support arms presently in use often require that a screw handle or wing nut be used to loosen and tighten joints for repositioning the device being supported. This is especially true when the device is relatively heavy, such as a flat-screened computer monitor. Some articulated support arms use pre-loaded clutches at the joints; these, however, are not aesthetically pleasing as they expose the clutch plates, springs, washers, and nuts, that constitute the clutch assembly, to view. Another problem with some conventional clutched joints is that they create the need to route power cords or cables around the open clutch assembly. This creates additional possibilities for damage to the cable or cord and further detracts from the aesthetic appeal of the assembly.
Ball-type joints are capable of a limited degree of universal movement when a cable or line is concealed within the joint. However, this type of joint usually requires a wing nut or hand screw type of tightener. Since the ball joint relies on its surface area for friction, the weight of many of the loads to be supported by a ball-type joint would require a large ball. Besides disturbing the aesthetic aspect, such large ball joints allow no provision for fine tuning of the amount of friction needed without external wing nuts or hand screws. Therefore, the most practical use of a ball joint is not when it is used as an offset joint but when a segment of a large spherical surface sits directly under the load, which is a common way many CRT computer monitors are presently supported.